Gas-engine.



i UNITED STATES Patented January 24, 1905.

PATENT OFFICE.

ALBERT E. DoMAN, or Eri-BRIDGE, NEW ironic SPECIFICATION forming part of Letters Patentv No. 780,556, dated January 24, 1905.

Application led'April 20, 1903. Serial No. 153,462.

To all whom t may concern:

Be it known that I, ALBERT E. DouAN, of

.Elbridga in the county of Onondaga, in the through a suitable passage connecting the` crank-chamber with the explosion-chamber.

Nowwhen the piston returns on its instroken the fresh explosive mixture is compressed in the inner end of the explosion-chamber and at the proper time is ignited, whereupon the expanded gases force the piston outwardly and are iinally discharged under considerable pressure through an exhaust-port, which is usually provided in the side wall of the cylinvder at or near lthe limit of the outstroke of the piston.

I have thus briefly described the operation of an ordinary two-cycle engine for the purpose of more clearly pointing out its mechanical and economical defects and disadvantages, which I have sought to overcome in the improvements hereinafter described. In this class of gas-engines the inlet and exhaust ports are located at the extreme outer end of the explosion-chamber, or rather at or near the limit o f the outward stroke of the piston,

and the piston is generally provided with a` deiiector-plate on its inner end to deflect the infiowing mixture inwardly along one side of the explosion-chamber, while the spent gases are supposed to pass in a reverse direction along the opposite side of said chamber and out through the exhaust-port when the latter is uncovered. The inflowing mixture enters the explosion-chamber at a much lower temperature than that of the burned gases, and this, together with the fact that the inlet and exhaust port-s are located at the same end of ough cleansing of the explosion-chamber, as will be readily seen. more or less of the expended gases are mixed and compressed with each fresh charge ot live gases, thereby reducing the volume of the live gases in the compression-space of the cylinder and also reducing the possible eiiiciency and power of the engine. It is also obvious that when a single exhaust-port is lo-.

cated as described the heated gases acting expansively upon the piston to impel it outwardly are discharged to atmosphere under high pressure, and therefore with a loud report or noise, which of course is a serious objection and represents a considerable `loss of energy'. The intensity of this noise may be materially reduced bythe use of mufilers; but under such conditions a degree ot' back pressure is produced upon the piston which materially reduces the working efficiency of the engine. In some instances a throttlevalve may be employed to reduce the quantity of the mixture admitted to the explosionchamber for the purpose of reducing the pressure and diminishing the inten'sityof the report at the exhaust; but this not only reduces the working `power of the exploded charge, but the'inflow of the reduced amount of fresh mixture is insufficient either in force or quantity to expel the burned gases at the exhaust.

The objects of my present invention may be summarized as follows: iirst, to introduce the explosive mixture into the explosionchamber in quantities proportionate to the work required of the engine-#1,'. e., a light charge for light work and a heavier charge for heavier work-so that only the live gases are compressed free from burned gases; second, to compress the fresh mixture during only a portion of the compression-stroke of the piston, but permitting the exploded charge to exert its full expansive force upon the piston through its entire outward stroke, so that when a small charge is ignited and expanded to the full limit of the outward stroke it is exhausted at a very low pressure andwith little noise; third, to thoroughly and automatically cleanse the cylinder from spent gases after each impulse, whereby only the fresh gases are compressed and expanded;

fourth, to not only avoid any back pressure It is now apparent that IOO gases to exhaust more freely at or near atmospheric pressure after exerting its full expansive force upon the piston; fifth, to regulate the speed and power of a two-cyclegasengine by the operation of a single controlling member, such as a hand-lever. It will thus be seen that my aim is to utilize the expansive force of a minimum quantity of fresh gas in the development of a greater degree of power and speed than has heretofore been practiced and to exhaust the burned gases at a low pressure without the use of muiiiers.

1n the drawings, Figure 1 is a side elevation, partly in section, of a two-cycle gas-engine embodying the features of my invention. Fig. 2 is a sectional View taken on line 2 2, Fig. 1. Fig. 3 is an end elevation of the parts seen in Fig. 1, showing particularly the valve-controlling mechanism.

Similar reference characters indicate corresponding parts in all the views.

This engine consists, essentially, of a cylinder 1, a piston Q movable in the cylinder, a crank-case 3, inclosing the open end of the cylinder for forming a suitable compressionchamber, and a crank-shaft 4, which is journaled in the end walls of the crank-case and is provided with an inner eounterbalance 4' and an outer balance-wheel 11, the purposes of which are well known. The cylinder 1 is provided with the usual explosion-chamber 5 and inlet and exhaust ports 6 and 7, which are formed in the side walls of the cylinder at the base of the explosion-chamber at or near the limit of the outward stroke of the piston, while the crank-case is provided with an inlet 8 and an outlet 9, which is connected to the port 6 by means of a conduit 10. The explosive mixture is drawn into the crankcase by suction due tothe instroke of the piston and is there compressed by the outstroke of the piston and forced through the conduit 10, so as to enter the explosion-chamber under pressure when the inlet-port 6 is uncovered, a suitable check-valve 11 being interposed in the inlet 8 to prevent backflow of the mixture. Assuming now that the head of the cylinder is permanently closed, as in the usual type of the two-cycle engines, then the introduction of the fresh mixture, which is necessarily of lower temperature than the previously burned or exploded gases, tends to not only retard the outiiow of the latter, but actually compresses a large percentage of the burned gases in the head of the cylinder even when a delector-plate is employed, so that when the piston moves inwardly these burned gases are mixed and compressed with the live gases. The piston is thus compelled to compress the gases through its full inward stroke, and owing to the fact that a large percentage of these compressed gases have been previously devitalized the power required to compress this vitiated excess is practically wasted, and

aside from the loud report of the exhaust the engine is always laboring under great disadvantages and loss of both power and fuel. In order to overcome these several defects and objections and to carry out the objects previously enumerated, l provide the cylinder l with an auxiliary exhaust port or opening 1Q, which is preferably located centrally in the head of the cylinder and discharges to atmosphere through a suitable passage 12. This auxiliary exhaust-port is provided with an automatically-closingvalve13, which preferably opens inwardly into the upper end of the explosion-chamber and is mounted upon an outwardly-extending stem 14, which is guided in apertures in the cylinder-head and is provided with outer and intermediate shoulders .15 and 16. A spring' 17 is interposed between the outer shoulder 15 and adjacent wall of the cylinder-head and serves to automatically close the valve 13, said valve being opened at regular intervals by means of a lever 18, which is fulcrumed at 19 and is engaged with thcshoulder 16, whereby when the lever is rocked in the manner hereinafter described the valve is opened inwardly. The movements of this valve 13 are synchronized with the movement of the piston 2 in such manner that the valve begins to open at about the same time that the port 7 at the opposite end of the explosionchamber is uncovered by the outward movement of the piston and remains open during a portion of the return upstroke el.' said piston or until the burned gases are entirely expelled from the cylinder partially through the exhaust-port 7, but mainly through the exhaust 12 in the head of the cylinder, whereupon the valve 13 is automatically closed and remains closed during the remainder of the instroke of the piston and also during the full outward stroke. It is thus seen that the live gases only are compressed in the head end ol the cylinder during only a portion of the iustroke of the piston, where they are ignited by any well-known igniting device, as terminals 18 of an electric circuit, not necessary to herein illustrate or describe, as the igniting device forms no part of my present invention. It will also be apparent that the expansive force of the ignited charge acts upon the piston through its full outward stroke, and owing to the fact that the charge previously admitted was free from burned gases and compressed during only a part of the instroke of the piston the pressure at the exhaust through the port 7 when uncovered by the outward movement of the piston is reduced to a minimum, and therefore obviates the usual loud report or noise which is incidental to the compression of the gases through the full inward stroke of the piston. Furthermore, by providing an exhaust-opening at each enel of the explosion-chainber operating in the manner described, the pressure heing lowered at the time of the exhaust, the relOO llO

permit the spring 17 to automatically close the lthereon.

of the cylinder, I provide the piston with a substantially central discharge-opening 19, which extends inwardly from the periphery of the piston and communicates with the in- -let-port 6 when the piston reaches the limit of its outward stroke, so that the gases are discharged centrally into the ex plosion-chamber and entirelyacross the head of the cylinder whereby the larger part of the burned gases are forced into the head end of the pylinder to be expelled through the outlet 12, while any portion of the burned gases which may remain in thevv base' of the explosionchamber can exhaust through the port 7 It is desirable to regulate the charge of exy plosive vmixture to harmonize with the work required of the engine,so that when only a light work is required a correspondingly light charge may be admitted, compressed, and expanded, while, on the other hand, when a heavier work is required a greater quantity of the explosive mixture is likewise compressed and expandedgpbut in neither c'ase are the fresh gases compressed during the full inward stroke of the piston, while in all cases the expansive force of the charge is exerted 22, an eccentric 23, and connections 24 and 25, i

the cam 22 being pivotally mounted at- 26 upon one end ofthe rod 25,which is moved in a guide 27 on the cylinder 1. The eccentric 23 is secured to the crank-shaft 11 and receives one end of the'connection 24:, the opposite end being connected to the rod 25, whereby the rotation of the eccentric imparts a reciprocating motion to the rod 25 and. cam 22,mounted This cam 22 is connected to the valve 21 at one side of its axis by means of a connecting-rod 28,-which is provided with an elongated slot 29 for receiving a pivotal pin 30, the latter being located at one side of the pivot 26 and is normally held against the upper end wall of the slot by meansof a spring 31, which operates to rock the cam 22 under the Aadjacent end of the'lever 18. preferably terminates in an abrupt end 32, so that when the eccentric operates `to open the valve through the medium of the connections 211 and 25 the camwhich bears against the outervend of the lever 18 is rocked upon the pivot 30 out from under. the lever, so as to rlhis cam valve immediately upon the expulsion of the burned gases from the explosion-chamber.

It may be stated here that the eccentric 23 is adjusted or set so that its maximum upward throw is a little later than the limit of the outward stroke of the piston; but the valve 13 begins to open at about the same time that the port7 is Runcovered by the outward stroke of the piston, and the further movement of the eccentric continues to rock the cam 22 Vout from under the lever 18 during a part of the upstroke of said piston, the cam being adjusted sothat itsend 32 leaves the lever 18 at about the same time that the burned gases are entirely expelled from the explosion-chamber, whereupon the spring 17 immediately closes the valve 13, and the mixture is then compressed into the upper end of the chamber and ignited and expand ed in the manner previously described. It now becomes apparent that the live gases only are compressed during a portion of the compressionstroke of the piston, and while the expansive forceof the exploded gases is exerted through the fulloutward stroke of the piston the charge admitted and compressed in .the explosionchamber is no more than is necessary to fill the space after the spent gases are exhausted, thus giving an increased eficiency to the engine,

By operating the valve 2O to vary the quantity of mixture admitted to the explosionchamber according to the work to be done it also becomes necessary to vary the time of movement of the valve 13, soas to allow the escape of all of the burned gases, but to prevent the escape of any part of the new charge. This is accomplished by connecting the cam 22 to the throttle-valve 2O in the manner previously described, so that any movement toward opening the throttlevalve 2O will oper- `ate to throw the pointof the cam 22 outwardly Assuming the piston to be at the limit of its IOO downward stroke, as seen in thedrawings, at

which time the inlet-port 6 and exhaust-ports 7 and 12 are open and the fresh explosive mixture is discharged centrally into the base of the explosion-chamber, then the upward stroke of the piston causes the burned gases `in the upper end of the chamber to be expelled through the exhaust-port 12, this occurring through only a portion of saidv upstroke,

' wherebythe valve 13 is immediately closed by forcing the cam 22 from under the lever 18 and .permitting the spring 17 to operate.

During the continued upward stroke of the piston the gases are compressed and ignited and then expanded and exert their expansive force through the full outward stroke of the piston, whereupon the operation is repeated. After each impulse of the piston the cylinder is thoroughly cleansed from burned gases by the inflowing mixture and the following upstroke of the piston, as described, so that only the fresh gases are compressed during a part of the upstroke of the piston. By operating the valve 2O the quantity of gas admitted may be proportioned to the Work required, and the speed and power are thus controlled by a single operatingmember. Furthermore, asidefrom the fact that the exploded charge acts expansively upon the piston through its entire outward stroke the pressure is reduced at the exhaust, soy that it is discharged at or near atmospheric pressure, thereby avoiding any objectionable noise.

' Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-- l. In a two-cycle gas-engine, a cylinder, a crank-case inclosing one end of the cylinder,'a self-closing valved outlet in the opposite end of the cylinder, a conduit connecting the interiors of the cylinder and crank-case, a piston operatively connected to open the valve, a manually-operated valve in the conduit to control the amount of mixture admitted to the cylinder and connected to the irstnamed valve to vary the time of its closing to correspond to the amount of mixture present in the cylinder.

2. In a two-cycle gas-engine, a cylinder, a piston, a crank-case inclosing one end of the cylinder and having an inlet, the opposite end of the cylinder having an outlet-opening to atmosphere, an automatically-closing valve for the outlet, automatic means to open the valve when the piston approaches the limit of its outward stroke and to hold it open during part of the instroke of the piston, a conduit connecting the interiors of the crank-case and cylinder, a valve in the conduit, and connections between the latter valve and said means whereby the former valve is caused to close at different positions in the upstroke of the piston according to the position of the latter valve to compress only the fresh gases present in the cylinder.

3. In a gas-engine, a cylinder having an explosion-chamber in one end and a compressionchamber in its other end, the explosion-chamber being provided with an inlet-port and an outlet-passage and the compression-chamber having' an inlet for the explosive mixture, the inlet of the explosion-chamber communicating with the compression-chamber and the outlet of said explosion-chamber opening' to atmosphere, anormally closed valve in the outlet-opening, a piston, a crank-shaft, an eccentric operatively connected and timed to open the valve when the piston approaches the limit of its outward stroke, and a valve in the connection between the explosion and compression chambers operatively connected to the former valve to change the time o'f operation relative to the movement of the piston.

4. A gas-engine having an explosion-chamber in one end and a com pression-chamber in its opposite end, the connincssion-chainber having an inlet for the explosive mixture, a check-valve in the inletopening inwardly when checking the outliow of the gases, a conduit connecting the compression-chamber with the explosion -chamber, said explosionchamber having its end provided with an outlet opening to atmosphere, a manually-opcrated valve in the conduit for regulating thc quantity of live gases admitted to the explosion-chalnber, a second valve in the outlet of the explosionchamber, means for automatically' closing said valve, a lever for opening the valve, a cam for operating the lever, means actuated by one ol the moving parts of the engine and connected to operate the caln and connections between the cam and manually-operated valve whereby the position of the cam may be varied irrespective of the lever for permitting the automaticclosing of the valveat different positions in the movement of the piston.

5. In a gas-engine, the combination with an explosion-chamber having an inlet-port and an outlet-passage, a compression-cham]ier connected to the inlet-port and having an intake for the fresh gases, a self-closing valve in the outlet-passage, a second valve in the connection between said chambers to control the supply of fresh gases to the explosion-chamber, a piston and connections between the piston and first-named valve whereby the latter is caused to open at the limit of the outstroke of the piston and to remain open during part of the upstrokc of said piston, and connections between said valves whereby the partial closing of the second valve eflccts a later closing of the first-named valve.

6. In a gas-engine, an explosion-chamber having an intake and an outlet, a manuallyoperated valve for the intake, a self-closing valve for the outlet remaining closed till the intake is uncovered by the piston, a piston opening and closing the intake and operatively connected to effect the opening of the outletvalve when it approaches the limit of its outstroke and to hold said valve open during part of the instroke and connections between the valves whereby the position of the intakevalve effects and determines the time ol closing the outlet-valve.

ln witness whereof I, have hereunto set my hand this 13th day of April, 1903.

ALBERT IC. DOMAN.

IVitnesses:

FRED. DYE, A. E. BROWN.

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